Nowadays, companies in the sector of distribution and marketing of fruit and vegetable products make ever-increasing use of highly automated lines and systems, which are used to carry out the necessary activities of movement, sizing, checking and packaging of fruit and vegetables.
In fact, as is known, only by way of a particularly high degree of automation it is possible to achieve high production volumes (such as, indeed, those required by the large-scale retail trade), while at the same time containing the processing times and the associated costs (of labor and logistics, especially).
Moreover, it should be noted that the peculiarity of each fruit and vegetable product, in terms of shape, size, structure, weight, defects, ripening path etc., impose different treatments and, more usually, pose different problems for makers of processing assemblies; therefore, dedicated adapted lines are often specially designed for each type of fruit (or vegetable).
In such context, one of the fruit and vegetable products that requires the greatest care, forcing designers to go to extremes, is without doubt the pear, whose particular shape structure leads to several difficulties, owing to the frequent impossibility of controlling its movement and placement with precision.
In more detail in fact, it should be noted that dedicated lines for the industrial processing of pears have, among other tasks, the task of weighing each one of them, while they are being moved along a predefined path.
According to conventional methods, the weighing is performed by a load cell conveniently arranged along the line, so as to act on each pear in transit, while this is conveyed toward the stations downstream by adapted containment units (sometimes called “cups”).
The load cell is therefore designed to weigh each cup and, with it, the pear conveyed thereby.
Such implementation solution is not however devoid of drawbacks.
It should be noted in fact that each pear is deposited on the line at an upstream station, at which each fruit is released and transferred to a corresponding cup by gravity and/or rolling, optionally by way of the use of special delivery and transfer elements.
In any case, in the moments following the delivery (and during its travel along the line), the pear can randomly and entirely unpredictably vary its arrangement, by oscillating or rotating about its center of gravity, and thus it is possible for it to be moved according to different inclinations.
With the variation of inclinations, especially when the pear tips on one side, the number of cups on which that pear rests and distributes its weight (often not evenly, moreover) also varies.
Furthermore, more simply, it should be noted that the number of cups on which the pear distributes the weight can vary as a function of the size of that pear (again, this is totally unpredictable).
It thus appears evident that when such circumstance arises, the load cell (which as has been seen checks in sequence the weight of each cup in transit) will perform a measurement that is totally incorrect, rendering the entire activity unreliable and ineffective.
Moreover, it is likewise clear that the problem cannot be resolved by using load cells that are designed in advance to act on pairs of adjacent cups, or on another number of contiguous cups chosen at installation time, since the random nature of the size and of the arrangement assumed by each pear (and therefore of the number of cups affected in each instance) would still make the measurement unreliable.